1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to an active-matrix type liquid crystal display device.
2. Description of the Related Art
In an active-matrix type liquid crystal display device, gate signal lines which are extended in the x direction and are arranged in parallel in the y direction and drain signal lines which are extended in the y direction and are arranged in parallel in the x direction are formed on a liquid-crystal-side surface of one substrate out of respective substrates which are arranged to face each other in an opposed manner while sandwiching liquid crystal therebetween.
Respective regions which are surrounded by these respective signal lines constitute pixel regions and each pixel region is provided with a thin film transistor which is driven by a scanning signal supplied from the gate signal line and a pixel electrode to which a video signal is supplied from the drain signal line through the thin film transistor.
The pixel electrode generates an electric field between the pixel electrode and a counter electrode which is arranged in an opposed manner by way of the liquid crystal and liquid crystal is driven by this electric field such that the light transmittance thereof is changed.
Further, the pixel region is usually provided with a capacitive element between the pixel electrode and the signal line having a stable potential for storing the video signal supplied to the pixel electrode for a relatively long time.